Animations and Models with Extra or Missing Bones

I read that Unity's animation system can adapt animations made for one biped model to another biped model. But how well does that work if the bones were to differ, such as when you have non-human bipeds?

Like, suppose I made a walking animation for a human model. Would it be able to adapt that animation to an angel model that adds wing bones? What if I made a walking animation for a demon model that had wing and a tail? If that animation were applied to a humanoid, would it just cull the wing and tail portions of the animation?

I ask this because I will be creating something with demi-human characters that add extra limbs or appendages, and I would rather not have to recreate animations for each body type.